This invention relates in general to friction clutches and in particular to an improved structure for a support plate and friction element for a driven disc assembly in such a clutch.
Clutches are well known devices which are frequently employed in vehicles to selectively connect a source of rotational power, such as the crankshaft of an engine, to a driven mechanism, such as a transmission. Typically, a cover of the clutch is connected to a flywheel carried on the end of the engine crankshaft for rotation therewith. Between the flywheel and the clutch cover, a pressure plate is disposed. The pressure plate is connected for rotation with the flywheel and the cover, but is permitted to move axially relative thereto. A shift lever assembly is provided for selectively moving the pressure plate back and forth in the axial direction.
A driven disc assembly is disposed within the clutch between the pressure plate and the flywheel. The driven disc assembly is carried on an output shaft of the clutch, which forms the input to the transmission. The driven disc assembly includes a hub, which is splined onto the output shaft, and a support plate which is mounted on the hub for limited rotational movement. A plurality of friction elements are usually secured to the outer ends of the support plate. Springs or similar torsion dampening devices are provided between the support plate and the hub. When the pressure plate is moved toward the flywheel, the friction elements of the support plate are frictionally engaged therebetween so as to cause the output shaft of the clutch to rotate with the flywheel, the cover, and the pressure plate. When the pressure plate is moved away from the flywheel, the driven disc assembly is released from such frictional engagement so as to disconnect this driving connection.
As the driven disc assembly is engaged and disengaged, friction causes heat to be generated. Excessive heat can cause a breakdown in the facings of the friction element. Heat can also cause warping and cracking of the support plate, resulting in premature failure. Accordingly, it would be desirable to provide a driven disc assembly which reduces the amount of undesirable heat generated during frictional engagement and disengagement of the clutch.